Collaborative Research: Understanding the Impacts of Ice Storms on Forest Ecosystems of the Northeastern United States

冰暴是全球温带和北方森林地区常见的强烈冬季天气事件。这些风暴能够对森林生态系统造成灾难性的短期生态和社会经济影响，因为它们会造成树枝断裂和树木在重冰负荷下倒塌。它们的遗产还可以通过森林生产力和物种组成的变化而长期存在；森林害虫和病原体的毒力；而且由于更多的燃料负荷，火灾的风险也会增加。尽管冰暴在形成森林生态系统方面发挥着重要作用，但对冰暴及其影响的了解仍然有限。由于冰暴在时间和空间上的不可预测性，过去的调查在很大程度上局限于大风暴之后的个案研究。美国东北部、加拿大东部和其他地方的冰暴的严重程度提高了对这些风暴在塑造未来森林中的作用的更明确的需要。新罕布什尔州哈伯德布鲁克实验森林的科学家们将开展一个多方面的研究项目，包括一项新的冰暴操纵实验、长期野外数据、气候和生态系统建模。这项研究将使科学界、土地管理者和有关公众更深入地了解这些强大的极端冬季天气事件对北方阔叶林生态系统动态的影响。这个综合研究项目是建立在哈伯德布鲁克和该地区之前工作的基础上的，包括2012年进行的冰暴试验；关于森林生态系统对“1998年冰暴”的响应的重要研究机构；还有一组新的历史气候重建，可以量化导致冰暴的气象条件。具体而言，研究人员将：(i)开发高分辨率全球气候模式模拟，以评估未来气候变化下冰暴的严重程度、频率和范围；（ii）评估生态系统对四种不同强度和两种实验冰事件频率的短期（2-3年）响应；（iii）评估森林植被对1998年风暴的长期（17年以上）反应；（iv）利用实验结果和长期观测结果，完善已建立的森林生态系统生物地球化学模型，模拟冰暴扰动；(v)利用高分辨率气候模拟结果推动改进的生物地球化学模型，预测未来冰风暴对北方阔叶林生态系统通量和碳氮库的影响。这项研究将与更广泛的影响相结合，包括：(i)使用传感器技术吸引STEM残疾学生参与研究；（ii）与当地利益相关者就冰暴的影响进行对话；（iii）制作有关冰暴形成及其与极端事件和气候变化的关系的录像；（四）本科生、研究生和博士后培养。

Ice storms are powerful winter weather events common to temperate and boreal forest regions worldwide. These storms are capable of catastrophic short-term ecological and socio-economic impacts on forest ecosystems due to branch breakage and toppling of trees under heavy ice loads. Their legacy can also persist over the longer-term through changes in forest productivity and species composition; the virulence of forest pests and pathogens; and increased risk of fire due to greater fire fuel loads. Despite their influential role in shaping forest ecosystems, knowledge of ice storms and their impacts remains limited. The temporally and spatially unpredictable nature of ice storms has largely confined past investigations to case studies following major storms. The severity of ice storms in the northeastern United States, Eastern Canada and elsewhere has heightened the need for greater clarity on the role of these storms in shaping future forests. Scientists at the Hubbard Brook Experimental Forest in NH will conduct a multi-faceted program of research that includes a novel ice storm manipulation experiment, long-term field data, and climate and ecosystem modeling. This research will provide the scientific community, land managers and the concerned public greater insight on the impacts of these powerful, and extreme winter weather events on the ecosystem dynamics of northern hardwood forests.This integrated program of research is built on a foundation of previous work at Hubbard Brook and the region, including a pilot ice storm experiment conducted in 2012; a significant body of research on the forest ecosystem response to the severe "Ice Storm of 1998"; and a new set of historical climate reconstructions which allow for the quantification of the meteorological conditions that lead to ice storms. Specifically, the investigators will: (i) develop high-resolution global climate model simulations to evaluate the severity, frequency and extent of ice storms under future changing climate; (ii) evaluate short-term (2-3 year) ecosystem response to four different intensities and two frequencies of experimental ice events; (iii) evaluate longer-term (17+ years) response of forest vegetation to the 1998 storm; (iv) use results from the experiment and the long term observations to refine an established forest ecosystem biogeochemical model to simulate ice-storm disturbance; and (v) use the results from the high-resolution climate simulations to drive the improved biogeochemical model to project future ice storm impacts on ecosystem fluxes and pools of carbon and nitrogen in a northern hardwood forest. This research will be integrated with broader impacts involving: (i) the use of sensor technology to engage STEM students with disabilities in the study; (ii) a dialog on the impacts of ice storms with local stakeholders; (iii) the production of a video on the making of an ice storm and relevance to extreme events and climate change; and (iv) undergraduate, graduate and post-doctoral training.